Practice question

Go with C — Secondary active transport. Within Excretory System, that statement lines up with the standard definition and the usual exam wording you’ll see. In plain terms, the functional job described in the stem is exactly what Secondary active transport does in Excretory System. Holding that picture in mind makes Secondary active transport feel natural rather than something you only memorise. Link the term to a real body example (organ, tissue, or ion flow) so the idea stays concrete under exam pressure. A short mental diagram helps — start from stimulus or structure, follow the pathway, and stop at the functional result described by Secondary active transport.